Science and music hurtling earthwards at eye-watering velocity

Tag: NASA

Earlier today NASA hosted a Hangout on Google+. Through that social media channel a group of schools and kids were able to ask live questions to two astronauts on the ground. Even more exciting is they were able to link in the middle of the Hangout to three astronauts on the International Space Station. And more exciting yet was that the entire world could participate by asking questions via YouTube, Facebook, Twitter, and Google+.

It only lasted an hour. I didn’t join live because it happened between 2 and 3am Sydney time, but I’ve just finished watching the replay on YouTube. You can too:

The fact that people can go to space and live there for months at a time is amazing. The fact that that place lets us do research there that’s not possible anywhere on Earth is incredible. But the fact that those people, in those places, can use modern communications technology to have a live, interactive session with all of us is world-changing. How many kids might be inspired by taking part in this sort of thing? It’s thrilling.

NASA’s Solar Dynamics Observatory – launched into space on February 11 – has sent back some amazing images of our Sun. Click here for several series of animated images that show flares, eruptions, and thermal currents, captured in spectra we can’t see with our own eyes. The Sun is an incredibly dynamic furnace is the sky, and is constantly churning and flaring and bubbling away up there.

The first vid – of the STS-125 (the recent Atlantis) launch – is long, but soooo worth it. In fact, the first seven minutes cover the launch, booster separation, and splash-down; it’s then shown again from other positions and angles (but all are worth it – the second sequence, starting at about 07:30, has audio).

Tomorrow evening (US eastern time) is the earliest window in which NASA’s Kepler mission may launch. This is very exciting because Kepler’s main mission is to locate planets that are similar, and in similar positions, to our own. Planets like Earth are the ones where we’d be most likely to find life as we know it.

Nearly all of the planets we’ve spotted that are located outside our own Solar System have so far been gas giants like Jupiter and Saturn. They’re easy to spot, though, because they’re big and hot. Kepler will find smaller, rockier, Earth-like planets.

There’s a huge amount of really fascinating science, from the general to the detailed, on the mission page. Here are some excerpts I really like.

How will Kepler look for extrasolar planets? By looking at stars, and watching for signs that something has moved across the front of them:

The Kepler spacecraft…will orbit our own Sun, trailing behind Earth in its orbit, and stay pointed at Cygnus starfield for 3.5 years to watch for drops in brightness that happen when an orbiting planet crosses (transits) in front of the star. Cygnus was chosen because it has a very rich starfield and is in an area of sky where the Sun will not get in the way of the spacecraft’s view for its entire orbit.

How does a transit tell us that there’s a planet there?

Transits by terrestrial planets produce a small change in a star’s brightness of about 1/10,000 (100 parts per million, ppm), lasting for 2 to 16 hours. This change must be absolutely periodic if it is caused by a planet. In addition, all transits produced by the same planet must be of the same change in brightness and last the same amount of time, thus providing a highly repeatable signal and robust detection method.

Once detected, the planet’s orbital size can be calculated from the period (how long it takes the planet to orbit once around the star) and the mass of the star using Kepler’s Third Law of planetary motion. The size of the planet is found from the depth of the transit (how much the brightness of the star drops) and the size of the star. From the orbital size and the temperature of the star, the planet’s characteristic temperature can be calculated. From this the question of whether or not the planet is habitable (not necessarily inhabited) can be answered.

What else will Kepler do?

The scientific objective of the Kepler Mission is to explore the structure and diversity of planetary systems. This is achieved by surveying a large sample of stars to:

Determine the percentage of terrestrial and larger planets there are in or near the habitable zone of a wide variety of stars;

Determine the distribution of sizes and shapes of the orbits of these planets;